8. The coordinates of an object moving in R3 at time t are x = t, y = t2, z = (2/3)t3. What is the distance traveled by the object between t = 0 and t = 3 ?
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A. 21 |
B. 27 |
C. 57 |
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D. 75 |
E. 3(46)1/2 |
Solution: The answer is A
The distance traveled by the object between t = 0 and t = 3 is given by the length of the arc created by the object in R3 from t = 0 to t = 3.
The length, L, of an arc in R3 from t = a to t = b is given by,
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Since

the distance traveled by the object is,
